Recording system



May 1, 1945. COLT ETAL 2,374,653

RECORDING SYSTEM Filed May 9, 1940 3 Sheets-Sheet l l l l I 1 ATTORNEY.

May 1, 1945. R. B. COLT ET AL RECORDING SYSTEM 3 Sheets-Sheet 2 FiledMay 9, 1940 lqs Q Q a in a IINVENTORS. Ru) e/"B 00/7 1*?61 7)??? C/m a'e// 'AT ORNEY y 1945. R. B. COLT ET AL 2,374,653

RECORDING 'SYSITEM Filed May 9, 1940 3 Sheets-Sheet 5 Ru? er .8. 60/7Ra/ 5. Che 0e// BY Y 1 AT ORNEY.

Patented May 1, i945 RECORDING SYSTEM Rutger Colt, Baltimore, Md, andRalph R. Chappell, Richmond, Va., asslgnors to Bendix AviationCorporation, South Bend, Ind, a corporation of Delaware Application May9, 1940, Serial No. 334,286

7 2 Claims.

This invention relates to recording systems and more particularly to adevice for making a written record of radio signals representative ofcertain atmospheric conditions.

Accurate indications of temperature, humidity, and pressure can beradiated from a balloon ascending to a height of approximately ten milesinto the air by means of a small radio transmitter carried thereby,which sends out different signals for the several atmospheric conditionsmentioned above. In order to correctly record these signals, varioussystems have been devised in the past, but have fail-ed to give asatisfactory record capable of accurate evaluation.

One of the objects of the present invention is the provision of a noveldevice which will accurately and faithfully record radio signalsrepresentative of different atmospheric conditions .Another object ofthe invention lies in the provision of a novel device adapted to make awritten or printed recording or variable conditions in a manner that canbe readily interpreted.

Other objects of the invention reside in the provision of a uniquephotoelectric circuit which, in combination with a novel marking system,gives a precise record of variable events, and in the provision of acompact mechanical arrangement incorporating mechanical and electronicelements in a novel manner to give a clear record of variable conditionswhich it is desired to measure.

Other objects will appear from a study of the specification and theattached drawings, throughout which like numerals designate like parts.

Certain features of the following disclosure are disclosed and claimedin our application, Serial No. 462,851, filed October 21, 1942, forRecording system (now Patent No. 2,348,711, dated May 16, 1944).

Fig. l is a plan view of one embodiment of the present invention;

Fig. 2 is a front elevation with certain parts in section, of therecording device shown in Fig. 1;

Fig. 3 is a cross-sectional view taken along the line 3-3 of Fig. 2;

Fig. 4 is a cross-sectional view taken along the line 4-4 of Fig. 2; and

Fig. 5 is a diagrammatic showing of the mechanical and electricalcircuits of the embodi sonde and is employed particularly in aviation todetermine flight conditions and in general meteorographic service todetermine atmospheric conditions at particular stations.

In one form of meteorograph, a carrier frequency of about sixty-fivemegacycles is modulated by a frequency on the order of one megacycle,which modulating frequency is interrupted at different audio-frequenciesrepresentative of different values of temperature, relative humidity,altitude, etc. These signals may be received and recorded by the use ofa device made in accordance with the present invention and interpretedby certain rules which it is not necessary to consider at this time.

Having particular reference to Figs. 1 and 2, the recording device ii]is composed of a rigid frame, having metal end-plates l l and i2, a basemember i3, and a transverse supporting rod M. A printing roll member i5is mounted between end-plates ii and i2 and its shaft it, which passesthrough holes in end members it and 52, terminates in gears ill and it,which are keyed to shaft to. Roll member 35 has a smooth, cylindricalsurface upon which is a helical ridge or projection 119 along it length.Frinting roll member i5 is driven through a suitable gear train by motor2t, shown in phantom in Fig, 2. A gear 2i is keyed to the shaft of motor23 and drives gear it through a suitable train. The gear 43 meshes witha larger gear 22, which is fixed to shaft 23, to which is also fixed adisc member Ell carrying a light source, designated generally as 25.Gear ll, being afiixed to shaft it with gear til, turns therewith andmeshes with gear 2%, which is fixed to shaft 2i carrying rotatable disc28 and the photoelectric cell, designated generally at 29.

A carriage, designated as so, is rockably mounted between end-plates iiand it upon a shaft ill which is loosely carried by end-plates it and 12in any suitable bearings. As shown more clearly in Figs. 3 and 4,carriage 3G is pivoted to move about shaft 34 and carries transverseframe member 32 which is rigidly connected at its ends to verticalrocker arms 33 and 34, which are mounted to rotate or oscillate aboutshaft 35 and carry the entire carriage member 30. Fixedly mounted withrespect to arms 33 and 34 are horizontally projecting arms 35, to whichare attached, by pivotal means 36, additional arms 31 which, attheirouter ends, are attached.to a transverse tapper bar 38,normallyheld slightly spaced above the raised portion or projection I 9 of rolll5 by mean of spring members 39. Vertical end members 40 are rigidlyattached to frame member 32 so as to form a part of carriage 30 rockableabout shaft 3| and these end members 40 are turned outwardly at theirforward end II to carry freely rotating spindles fl, upon which a copyribbon,

such as typewriter ribbon, is threaded, as will be v tegrally connectedto the ends of arms Bl and extend horizontally inwardly a sufficientdistance to bear upon the top surface of arms 35.

It will be seen, therefore (from Fig. 3), that arms 35 and 3? canberocked clockwise without relative angular motion, but that arms 3i andtapper bar 38 can be rotated counter-clockwise r with respect to arm 35through an arc limited by stop members ll at one end and projection iiiof printing roll it at the other end of its travel.

Rocker arm 3% has an integral extension Q8 which terminates in a camfollower 69 in engagement with heart-shaped cam member 50. Cam member bis rigidly fixed to shaft El and rotated at constant speed by means ofgear 26. Also carried on shaft 3i, adjacent end-plate ii, is a platemember 5! to which is rigidly connected a transversely extending stopmember 52.

One end of a spring member 53 is connected to the plate member 5i whichhas a vertically extending slot 54; therein. Lying in parallel relationto plate member El, and ,between it and end member II, is segmental gearmember 55 to which is attached the other end of spring 53 by means of alug 56 extending through slot 55 of plate 5!. Initial adjustment of barmember 38, to be slightly raised above projection i9 01 printing rolli5, is accomplished by adjusting screw members 57 with respect to stopmember 52 against the tension of spring 58 carried by rocker arm at. Itwill be readily seen then, that once every revolution of cam 56,carriage 30, including tapper bar 38, will be rocked clockwise for aninterval depending on the characteristics of cam 50, so that an operatormay inspect the marking made by tapper bar 38 upon sheet 59, and thusobtain a quick check On the proper operation of the recording device,

A second segmental gear member 58 is pivoted upon shaft i6, extendingthrough end-plate ii and fixedly connected by means of a key to handlemember 68 which lies closely adjacent end-plate l i. Upon pulling handleBil to the left, as shown in Fig. 4, the whole carriage assembly 30, aswell as plate 5!, and gear segment 55, will be rocked clockwise, andsimultaneously segment 58 will be rocked counter-clockwise, in order tofacilitate a change of record sheet 59, and for inspection purposes, aswill become apparent as the description proceeds.

ed upwardly upon energization of electromagnets 63, as will be laterdescribed. In order to maintain armature 65 spaced from theelectromagnets 63, when the latter are not energized, carriage member 30carries arms 66 to which is attached coil spring 61, having its oppositeend connected to lever arm 58, which is fixed to armature 65. Thetension of spring M can be adjusted by the screw and bolt arrangementas, so that when the electromagnets are de-energized, tapper bar 38 israised above roll I5, as shown in Fig. 3, and the armature 65 will bepositively held spaced from electromagnet 53, and yet will be readilyattracted thereto upon energization of the electromagnets, to cause arms35 and 3?, and tapper bar 38, to move downwardly against stop members36, whereupon the inertia of arms Bl and bar 33 will carry theseelements downwardly momentarily against the tension of springs 33, sothat tapper bar 38 will strike theprojection it of roll i5, and thusmark record sheet 59.

Tape rolls M are constantly rotated through a suitable gear arrangement,not shown (which also reverses their rotation to change the direction ofmovement of tape ill), by means of an electric motor ll, carried upontransverse frame member 32. It will be seen that the copy tape 10extends from one of the tape rolls l l, laterally to spindles 62 on oneside of carriage 30, down under tapper bar 38 and longitudinallythereof, up the other side of carriage 30, over spindles t2, and back tothe other of tape rolls M. Record sheet 59, which is marked duringtheoperation of the tapper bar 38, is carried upon a roll 72, rotatable,about a shaft 13, which i journalled at both its ends in plate members'16, which are keyed to gear segments 58 so as to rotate shaft 73 andguide members '15 which extend transverselybetween plates 76, aboutshaft is upon the pulling of handle to the left, as shown in Fig. 4. Therecord sheet is threaded from roll l2, over the top guide member 15, inbetween roll member i5 and tapper bar 38, thence to driving roll it,which is driven at constant speed, through a suitable gear train IT, bymotor 18. In order to impart the motion of driving roll it to recordsheet 59, tension rollers '19, carried upon finj gers so, areresiliently pressed against roll it by means of coil springs 8i, whichnormally urge In order to prevent rocking motion, due to the engagementof extension 8 with cam 50, from also causing rotation of gear segments55 and 58, handle 60 is normally held in place by a latch member iiiwhich engages with the notch or detent 62 inhandle member 60.

Frame member 32 carries two electromagnets, indicated generally at 63,which are rigidly suspended by any conventional means, such as nuts andbolts 64. An armature 65, carried by ext nsions of arms 35, ispositioned directly beneath electromagnets 63, and is adapted to besaw-act- ,the operation of the recording device.

fingers 88 toward each other, to increase the friction between drivingroll 15 and record sheet 59.

An apron- 82, extending transversely between and carried by end membersII and I2, guides the sheet 59 to the forward end of the recordingdevice iii, where it may be readily viewed by an operator, or cut ofi,without interference to The assembly of rollers and fingers l9 and 80 isreadily removed from frictional engagement with driving roll it for thepurpose of changin record sheets, since transverse supporting rod it,which carries this assembly, is swingable in an are about pivots 8 3 bymeans of arms 85, which carry rod It and are pivoted about point ti onend members ii and I2. Also, the assembly l98il is maintained infrictional engagement with driving roll 16 by means ofextensions 85 ofarms 85 which carry stud members releasably engageable with detents inend members ii and i2. Since roll 72 is freely journalled in members M,means indicated generally at ill, and comprising a plate membercarventional type, coact with slip-rings 89 to carry current to therotating light source irom'any suitable supply means, such as a batteryI23 of Fig. 5. Also, 98 designates a means for focus! ing light which isprojected to the left as viewed in Fig. 2 and intercepted, in theabsence of any opaque substance therebetween, by th photoelectric cell29, which is mounted to be rotated upon disc 28 and driven through gears26, I1, I8, etc., and through the printing roll I5- by means of motor28, at a speed synchronous with the rotation of the light source.

Brush 9| cooperates with slip-rings 92 to eonnect photoelectric cell 29with an amplifying and impulse generating circuit to be descnbed later.Interposed in the path of light between source 25 and photoelectric cell29 is a frequency meter 93, having a-pointer 94 which is adapted, aswill be described later, to vary in accordance with received radiosignals. Pointer 94 carries, at its outer extremity, a small flag member95 which is movable along with pointer 94 in an arc through which lightis projected during a portion of a cycle of rotation of light source 25;Meter 93 is carried within an opaque casing 96, which in turn, isrotatably mounted upon shaft 91, supported by pedestal member 98, uponbase member I3 to which the pedestal member 98 i securely fixed.Apertures 99 and I88 iii casing 96 permit light to traverse the casing,and aperture 99 is tapered at one end, as indicated at I8I of Fig. 3 fora purpose to be described later. Pedestal member 98 has an integralsupporting portion I 82 wh ch carries a worm gear I83, in suitablebearings I84, as well as a wheel I85 which meshes with worm I83. A dialI86 is rigidly connected to the shaift carrying worm gear I83 forrotatin met r casing 96 through a pulley, not shown, rotatable withwheel I85 which transmits rotation to casing 96 by virtue of the endlessbelt III'I. Current rings 89, as shown, by an electrical source, such asbattery I23. Since the gear trains at each end of printing roll I5 aremade to have the same value, it is apparent that discs 24 and 28 will berotated synchronously, and if lamp 25 and photoelectric cell 29 areinitially adjusted to be in the same horizontal plane, then-the lightfrom the lamp 25 will be directed to photoelectric cell 29, at everypoint in the circle through which both are rotated, and the light willbe intercepted only at those points at which opaque objects areinterposed. Assuming that the only opaque obiect is the pointer 94, thenlight will be interrupted at one point in each revolution of discs 28and 24, which point may vary, depending upon the position of pointer 94.In actual practice, the casing 96 of meter 93 also will interrupt thelight, but this has no efiect on the operation of the recorder, as willbe explained later. The output of photoelectric cell 29 is connected bya suitable slip-ring 92 to the vacuum tube amplifier [25, which may beof any conventional design, capable of amplifying the minute currents ofthe photoelectric cell. The output of the vacuum tube amplifier isconnected to the grid I26 of the gaseous triode I21 I i which may be ofthe type commonly known as thyratron. The anode I28 is connected througha. conductor I29 to the coils of electromagnets 63, thence throughconductor I3I and resistor I32 to the positive pole of a source ofpotential which may be the conventional B battery. The negative pole ofthe B batteryis connected to ground completing a circuit throughconductor I33, to the cathode I34 of tube I21. This circuit alsoincludes a condenser I35, which has a function that will be describedbelow.

It is a well known characteristic of thyratrons that the conductancedoes not change directly with grid potential, but that upon the grid at-40 taining a certaindefinite positive potential, ionfor operating ,meter93 is introduced thereto by means of terminals I88. which connect withany suitable leads to a radio receiver, as will be described later.

A diagrammatic representation of the recording device is shown in Fig.5, in' which I89 represents a radio antenna of any suitable type, suchas a dipole, connected to the input of a radio receiver II8, which istunable to the carrier frequency of the radiosonde described in thebeginning of the specification. This receiver may be of any type, suchas a superheterodyne, having an audio-frequency output which isconnected to frequency meter 99, having a movable pointer 94. As theradio transmitter sends forth signals at audio-frequencies dependingupon the dlii'erent atmospheric conditions being measured, pointer 94 ofmeter 93 is movable through an arc of approximately 90 degrees. A motor28, driven by any suitable source, not shown, rotates a disc 29 whichcarries a light source, such as lamp 25, and drives, through suitablegearing, heretofore described, a printing roll I5 with its helicalprojection I9 thereon. The other end of roll I 5 drives through suitablegearing, also heretofore described, a disc 28, carrying photoelectriccell 29. Light source 25 may be energized through slipization of the gascauses the anode-cathode conductance through the tube to increaseimmediately to its maximum value. 'Once the current flow has beenstarted by the grid, the latter has no further control and removal ofgrid potential does not aflect the anode-cathode current flow. Thecurrent flow can be stopped, however, by removing the anode potentialfor a slight interval, during which the gas de-ionizes. After currentfiow has been stopped for the de-ionizing interval,

full anode potential can be reapplied and the tube remainsnon-conductive until the grid reassumes its predetermined ignitionpotential, starting another cycle of operation similar to that justdescribed.

The vacuum tube amplifier I25 is so designed that it impresses aninstantaneous positive potenanode-cathode circuit across 1 the impulseof positive potential is impressed upon grid I26, tube I27! immediatelydischarges and an impulse of current flows through the an ode-cathodecircuit, including tapper bar magnets 63, momentarily energizing themand actuating tapper bar 98. Atthe same time, the discharge of tube I21causes the condenser I35 to discharge because of the low impedance ofthe ts plates. The

potential is thus removed from anode I28, allowing the tube to de-ionizeand be ready for the next impulse of grid current. Upon removal of anodepotential, condenser I85 is recharged through resistance I32, which is01 such value .as to rechargethe condenser in a predetermined interval.It will be seen, therefore, that in every cycle of rotation of lamp 25and photoelectric cell 29,

"there will be an impulse of potential on grid 8%,

' per bar 38 is attracted byelectromagnets 63 and caused to strikeagainst helical projection l9.

Since the opaque casing 96, in actual practice,

I interrupts the beam of light just as does pointer st, or its flagmember 95, it is necessary to prevent operation of the tapper bar uponrestoration of the light beam after it has been interrupted by casing96, and before it has been restored after interruption by pointer 96.Amplifier I25 has been designed so that only sudden (as distinguishedfrom gradual) restoration of the light beam to its full value will causeactuation of the thyratron circuit. Since such design is conventional inthe art, it is not discussed here. The gradual restoration of the lightbeam, after interruption, is not sufilcient to impress the necessarypositive potential upon grid I26 to ignite the thyrat'ron I21. After thelight beam has beeninterrupted by the opaque portion of casing as, it isrestored as the beam swings through the are including. aperture 99,which is tapered as lul so that the light beam, as it enters theaperture, is restored very gradually from the point of convergence ofthe tapered portion ID! to the point at which the aperture has itsmaximum width, which is greater than the cross-sectional trace of thelight beam in the plane of the aperture. It will be seen, therefore,that at only one point will the tapper bar 38 be energized, and thispoint will be immediately after the light beam has been interrupted byflag member 95 v of pointer 98.

By means of the worm and wheel 103, Hi l, and

the dial N16 for actuating the same, meter casing 96 can be rotatedthrough endless belt 1B1,

to move the entire meter assembly, including the radiosonde mentionedearlier in the specifloation, may be compared with a calibratedfrequency meter and any slight difierence between degrees of arc, thenfor every rotation of discs 25 and 28, only one rotation of printingroll I5 would be required, in order that tapper bar 38 might be able tostrike projection H9 at any point through its length. As a practicalmatter, however, meter 93 is restricted to an indicating arc of 90degrees. If printing roll i5is revolved only once for every revolutionof discs 29 and 28, then the portion of printing roll thatcould beutilized in the making of a record would be only onefourth its completelength, since for every 360 degrees of disc rotation there would be onlya 90 degree interval in which pointer 96 could cause operation of tapperbar 38-. .The gear train Tl, above described, is, therefore, made ofsuch value that for every rotation of-discs 24 and 28, printing roll I5will make four complete revolutions. Thus, the printed record can bespread completely across the width of printing roll I5. While 90 degreesseems a desirable indicating range for meter 93, it has been found thatmeters can be used in other ranges of arc, such as 120 degrees. Forpurposes of description, however, it can be assumed that the meterindicating range is 90 degrees of are.

While only one embodiment of the invention has been illustrated anddescribed, it will be understood that many changes may be made withoutexceeding the scope'of the present invention. It is, therefore, notintended to limit the inventionto the particular embodiment described,but only by the scope of the appended claims.

What is claimed is:

1. Apparatus for recording variable quantities which comprises a meterfor measuring such.

quantities said meter having a pointer movable through a definite arcand an opaque casing having a-transparent portion for the arc throughwhich said pointer is movable, a light source, -a printing roll and aphotoelectric cell, all being rotated in definitely related cycles, saidpointer being disposed so as to intercept a beam of light from saidlight source to said photoelectric cell once every cycle of rotation, atapper and marking mechanism disposed adjacent said printing roll, meansfor mounting a record sheet between said printing roll and said tapperand marking mechanism, and an electronic circuit connected to saidphotoelectric cell and said tapper mechanism for actuating the latterand marking a record in accordance with an indication of said meter.

2. In a recorder, a rotating light source, a synchronously rotatingphotoelectric cell, a printing roll having a helical ridge, said rollbeing movable at a fixed speed, a meter having a pointer movable, inresponse to the varying of conditions the minimum and maximum frequencyvalues of v possible .to make aperture 99 extend t ough 360 to berecorded, in a restricted arc of the same radius and axially spaced'fromand lying between the circles through which said light source andphotoelectric cell are rotated, a taper bar adjacent said roll andmovable thereagainst, means for moving a record sheet between saidtapper bar and said roll, and means connected to the output of saidphotoelectric cell for actuating said tapper bar toward said helicalridge upon interruption of light'from said source to said photoelectriccell by said movable pointer to form a record of indications of saidmeter.

RALPH R. CHAPPELL. RUTGER B. COLT.

